Development of serial-connection piezoelectric pumps

To achieve high output performance at low actuation voltage, serial-connection multi-chamber piezoelectric micropumps (SCMCP micropumps) with cantilever valves were introduced. The SCMCP micropumps, which can be produced using conventional production techniques and materials, have a multi-layer circular planar structure. The border-upon piezoelectric diaphragm actuators (PZT actuators) of a SCMCP micropump work in anti-phase, as a result of which the output performance is equal to that of several single-chamber piezoelectric micropump (SCP micropump) running in series. The theoretic study suggests that pumping performance of a SCMCP micropump depends on not only the characteristic and geometrical parameters of the PZT actuators, but also the number of the pump chambers. Both flowrate and backpressure of a SCMCP micropump can be enhanced to a certain extent in this way. Four piezoelectric micropumps with different chambers were fabricated and tested for comparison. The testing results show that all of the flowrate, backpressure and even optimal frequency of the SCMCP micropumps increase greatly with the rising of the chamber number. Both the maximum flowrate and pressure of the 4-chamber piezoelectric micropump are about four times of those of the SCP micropump at their respective optimal frequencies. The great advantage of a SCMCP micropump over a SCP micropump is that it can achieve high performance at a comparatively low driving voltage, which is helpful for the portable applications such as an implantable drug-delivery system.